title: Non-specific sex-differential effect of DTP vaccination may partially explain the excess girl child mortality in Ballabgarh, India.
abstract: OBJECTIVE
  To test the hypothesis that a gender differential exists in the effect on child mortality of BCG, DTP, measles vaccine as administered under programme conditions in Ballabgarh HDSS area.
  
  
  METHODS
  All live births in 28 villages of Ballabgarh block in North India from 2006 to 2011 were followed until 31 December 2011 or 36 months of age whichever was earlier. The period of analysis was divided into four time periods based on eligibility for vaccines under the national immunisation schedule (BCG for tuberculosis, primary and booster doses of diphtheria-tetanus-pertussis and measles). Cox proportional hazards regression was used to assess the association between sex and risk of mortality by vaccination status using age as the timescale in survival analysis and adjusting for wealth index, access to health care, the presence of a health facility in the village, parental education, type of family, birth order of the child and year of birth.
  
  
  RESULTS
  702 deaths (332 boys and 370 girls) occurred among 12,142 children in the cohort in the 3 years of follow-up giving a cumulative mortality rate of 57.5 per 1000 live births with 35% excess girl child mortality. Age at vaccination for the four vaccines did not differ by sex. There was significant excess mortality among girls after immunisation with DTP, for both primary (HR 1.65; 95% CI:1.17-2.32) and DTPb (2.21; 1.24-3.93) vaccinations. No significant excess morality among girls was noted after exposure to BCG 1.06 (0.67-1.67) or measles 1.34 (0.85-2.12) vaccine.
  
  
  CONCLUSIONS
  This study supports the contention that DTP vaccination is partially responsible for higher mortality among girls in this study population.
authors.affiliation: Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India; Department of Public Health and Clinical Medicine, Umeå Centre for Global Health Research, Umeå University, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Krishnan
authors.forename: R
authors.initials: R
authors.lastname: Srivastava
authors.forename: P
authors.initials: P
authors.lastname: Dwivedi
authors.forename: N
authors.initials: N
authors.lastname: Ng
authors.forename: P
authors.initials: P
authors.lastname: Byass
authors.forename: C S
authors.initials: CS
authors.lastname: Pandav
mesh_terms: D001500:BCG Vaccine / Q000009:adverse effects; D046688:Child Mortality; D002675:Child, Preschool; D015331:Cohort Studies; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007115:Immunization Schedule; D007194:India / Q000453:epidemiology; D007223:Infant; D008297:Male; D008458:Measles Vaccine / Q000009:adverse effects; D012737:Sex Factors; D016019:Survival Analysis; D014611:Vaccination / Q000401:mortality*
chemical_list: D001500:BCG Vaccine; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D008458:Measles Vaccine
keywords: DTP; girl; mortality; non-specific effects; vaccine